[Therapeutic effectiveness of thalidomide to multiple myeloma and its mechanism]

To observe the effective mechanism and side effects of thalidomide to multiple myeloma (MM).

Ten cases of MM were studied, of which 3 were previously untreated and 7 refractory or relapsed. Bone marrow microvascular density (MVD) was detected by factor-VIII related antigen and CD(34) immunohistological staining and serum concentration of vascular endothelial growth factor (VEGF) before and after treatment was determined by ELISA. The initial dosage of thalidomide was 100 approximately 200 mg/d with a weekly escalation of 50 mg/d to 450 approximately 650 mg/d. The therapeutic effectiveness is classified into partial remission, improvement and uneffective according to the decrease of serum M protein and bone marrow myeloma cells. Anemia, renal function and blood electrolytes were also observed.

Before treatment, MVD was 73.32 +/- 28.80 and 32.30 +/- 12.50 in MM and control group, respectively, (P < 0.01). MVD in MM group decreased to 56.12 +/- 19.34 after treatment, and was of significant difference (P < 0.05) as compared to the pretreatment value. However, there was still a significant difference as compared to control (56.12 +/- 19.34 vs 32.30 +/- 12.50, P < 0.01). The concentration of VEGF significantly decreased after treatment [from (178.23 +/- 26.56) ng/L to (78.48 +/- 19.98) ng/L, P < 0.01)]. The total effective rate was 70%. There were no serious side effects.

MVD and VEGF concentration were decreased obviously by thalidomide treatment. The dosage of 450 approximately 650 mg/d might be effective in refractory or initial MM.